Throughout history, people have been trying to find new ways to transport heavy loads across varying terrains and/or great distances. There is a long line of wheeled carriers that have been previously invented to assist people with transport such as, for example, a dolly, cart, sled, and wheel barrow. There have also been several carriers that require a person to tow or carry a load behind them. However, these carriers are typically meant to transport a load over short distances and are not meant to go over rough terrain without a human or animal bearing a large part of the load burden.
None of these items would be particularly helpful to a person wishing to backpack or camp in an area that requires hiking a great distance over rough terrain. The average backpacker carries a load ranging from 25-50 lbs. of mostly and typically essential items such as the backpack itself, a sleeping bag, tent, clothes, camp stove, utensils, food, and water. Commonly, a backpacker would carry these items over several miles, often times requiring a hike up very steep areas over a variety of terrains such as rocky, grassy, dirt, brushy, and often uneven areas with dips, holes and crevices. Depending on the individual, the load weight does not go much higher than 50 lbs. as this would create a lot of stress on the user and it would be difficult to travel with it over much distance in a reasonable length of time.
Primary issues that can prevent prior inventions from being able to carry loads over these terrains are a lack of maneuverability and balance. If the carrier has two wheels, it is not only heavier than a single wheel carrier but it is also very difficult to maneuver over a rough terrain that may be narrow or curving. Having a single wheel makes moving and maneuvering much easier. A single wheel permits running a load along a path that is barely wide enough to stand on, whereas two wheels require a wider path with a level terrain to keep the load from tipping.
There are single wheel carriers that may carry a load for a short distance, but these carriers have balancing issues, particularly when the load is greater than 20 lbs. The heavier the load, the more unbalanced it can tend to become. The more unbalanced it is, the more the load burden gets distributed from the carrier and onto the body of the user via the harness attaching the carrier to the body. This undesirable load redistribution puts strain on the overall body of the user, particularly the legs, making it more difficult to go further distances or transport the average, substantial weight of essentials required for overnight backpacking trips. Patent descriptions of prior inventions in the field of single-wheel personal towing devices generally do not provide clear, detailed specifics on how the device has solved the problem of maintaining hands-free balance when the device is being towed under heavy loads, particularly over rough, rutted, rocky ground that goes uphill or downhill.
For example, U.S. Pat. No. 7,484,737 ('737) is directed to a mono-wheel device which is capable of switching from a towing device to a backpack. The '737 device has two separate structures, described as a linkage and a frame. A user relies on a harness belt to tow a load and the back pack straps are only utilized when the user wishes to no longer tow the load but instead carry the load on the user's back. The back pack configuration is essentially a back pack having parallel straps and does not add any benefit when a load is being towed. The '737 patent does not describe a balancing mechanism that enables balance and/or stability when the carrier is under tow with a substantial weight. The '737 device also includes an embodiment having two wheels which would overcome the balancing problem inherent with a mono-wheel device but as noted above, the second wheel also adds additional weight and a lack of maneuverability.
Another prior example includes U.S. Pat. No. 5,385,355 ('355) which describes another mono-wheel device in which the towing part is attached to an apparatus having an external backpack frame with a standard backpack configuration in which the straps are parallel when worn by a user. With this device, the backpack harness attaches to a complicated single-point hitching mechanism which is asserted to assist the device with maneuverability. If the load were to roll and become unbalanced, the force of the weight shift would be transmitted directly to the user harness and would be tantamount to the loss of balance of a normal, heavily loaded backpack, which would tend a) to throw the user off balance or b) to twist the harness on the user's back and thus potentially cause the device to roll to the ground.
Accordingly, there is interest in a transport carrier that is capable of sustaining a balanced load with its weight resting primarily on the wheel to reduce the load burden on the user while at the same time providing maneuverability when traveling distances, in particular over varying rough terrains. In general contrast to patent descriptions of prior inventions in the field of mono-wheeled, multi-purpose transport carriers for towing loads, the present application provides clear, detailed descriptions of a unique balancing mechanism by which the present invention specifically solves the problem of maintaining hands-free balance when the mono-wheeled carrier is being towed under heavy loads, particularly over rough, rutted, rocky ground that goes uphill or downhill.